A novel molecular target, superoxide dismutase 1, in ALK inhibitor-resistant lung cancer cells, detected through proteomic analysis
Related Experiment Video
Updated: Jun 12, 2025
Author Spotlight: Advancements in Molecular Biomarker Testing for Non-Squamous Non-Small Cell Lung Cancer
Published on: September 8, 2023
Noriko Miyake1, Nobuaki Ochi2, Masami Takeyama2
1Department of General Internal Medicine 4, Kawasaki Medical School, Okayama, Japan; Kajiki Hospital, Okayama, Japan.
Backgrounds:
To the best of our knowledge, there are no reports of proteomic analysis for the identification of unknown proteins involved in resistance to anaplastic lymphoma kinase (ALK) inhibitors. In this study, we investigated the proteins involved in resistance to alectinib, a representative ALK inhibitor, through proteomic analysis and the possibility of overcoming resistance.
Methods:
An ALK-positive lung adenocarcinoma cell line (ABC-11) and the corresponding alectinib-resistant cell line (ABC-11/CHR2) were used. Two-dimensional difference gel electrophoresis (2D DIGE) was performed; the stained gel was scanned and the spots were analyzed using DeCyder TM2D 7.0. Mass spectrometry (MS) with the UltrafleXtreme matrix-assisted laser desorption ionization-tandem time-of-flight (MALDI-TOF/TOF) MS system was performed. For the MS/MS analysis, the samples were spotted on an AnchorChipTM 600 TF plate. The peptide masses obtained in the reflector positive mode were acquired at m/z of 400-6000. MS/MS data were searched against the NCBI protein databases. Growth inhibition was measured using an MTT assay. The isobologram and combination index were calculated based on the median-effect analysis. Western blotting was performed using antibodies, including superoxide dismutase (SOD) 1, MET, ERK, PARP, AKT, and BRCA1.
Results:
The 2D DIGE for ABC-11 and ABC-11/CHR2 showed different expression levels in about 2000 spots. SOD was identified from spots highly expressed in resistant strains. Western blotting also confirmed SOD1 overexpression in ABC-11/CHR2. siSOD1 enhanced the growth inhibitory effects of alectinib, increased cleaved PARP levels, and decreased pERK, pAKT, and BRCA1 levels with a combination of alectinib. In addition, the combination of LCS-1, an SOD1 inhibitor, and alectinib synergistically suppressed the growth in ABC-11/CHR2, but not in ABC-11.
Conclusions:
SOD1 overexpression is thought to be a mechanism for alectinib resistance, suggesting the possibility of overcoming resistance using SOD1 inhibitors.
Insights
Superoxide dismutase 1 (SOD1) overexpression drives resistance to alectinib in lung cancer. Inhibiting SOD1 resensitizes tumors to alectinib, offering a potential strategy to overcome treatment resistance.
Area of Science:
- Oncology
- Proteomics
- Molecular Biology
Background:
- Anaplastic lymphoma kinase (ALK) inhibitors are crucial for treating ALK-positive lung cancer.
- Mechanisms of resistance to ALK inhibitors, such as alectinib, are not fully understood.
- Proteomic analysis offers a novel approach to identify proteins involved in drug resistance.
Purpose of the Study:
- To identify proteins contributing to alectinib resistance in anaplastic lymphoma kinase-positive lung adenocarcinoma.
- To investigate strategies for overcoming alectinib resistance through proteomic insights.
Main Methods:
- Proteomic analysis using 2D DIGE and MALDI-TOF/TOF MS on alectinib-sensitive (ABC-11) and resistant (ABC-11/CHR2) cell lines.
- Validation of protein expression via Western blotting for superoxide dismutase 1 (SOD1), MET, ERK, PARP, AKT, and BRCA1.
- Assessment of drug efficacy using MTT assays, isobologram analysis, and combination index calculations.
Main Results:
- Proteomic analysis revealed differential expression in approximately 2000 protein spots between sensitive and resistant cell lines.
- Superoxide dismutase 1 (SOD1) was identified as significantly overexpressed in alectinib-resistant cells.
- siSOD1 or SOD1 inhibition (LCS-1) combined with alectinib synergistically inhibited growth in resistant cells, restoring sensitivity.
Conclusions:
- Overexpression of SOD1 is a key mechanism conferring resistance to alectinib in lung adenocarcinoma.
- Targeting SOD1, potentially with specific inhibitors, presents a promising therapeutic strategy to overcome alectinib resistance.
